Detonator



April 1968 F. R. THOMANEK 3,377,953

DETONATOR Filed July 13, 1966 INVENTOR F run z Rudolf Thomanek I I 2 byYi/VW M d/ WM ATTORNEYS United States Patent Oflice 3,377,953 DETONATORFranz Rudolf Thomanek, Sandizell 38 A, Landkreis Schrobenhausen, UpperBavaria, Germany Filed July 13, 1966, Ser. No. 564,871 Claims priority,application Ggrmany, Aug. 12, 1965,

s 7 Claims. Cl. 102-70 ABSTRACT OF THE DISCLOSURE Summary of theinvention This invention relates, in general, to the construction (if anexplosive charge and, in particular, to a new and useful explosivecharge or detonator having punctiform initiation of the detonation of ahigh intensity charge for obtaining 'an axially symmetrical detonationand wherein the explosive charge includes a fast acting explosiveembedded in a slower acting explosive.

In order to release in an explosive charge a detonation wave which meetsthe highest precision standards, it is necessary that the detonationwaves start geometrically exactly and that the intensity of theinitiation be as high as possible so thatthe detonation wave canpropagate in any direction at full velocity. Only by insuring bothcriteria will 'a satisfactory design of detonation wave be possible.

Tests have shown that hollow charges are particularly sensitive tounsymmetrical detonation waves. For this reason, it has been attemptedto make the detonation wave as punctiform as possible, for example, byselecting a thin rod-shaped detonator. Therefore, there is a limitationon the diameter of the rod which may be employed and no detonation willbe possible with a rod below a certain diameter depending on theproperties of the explosive and of the inert tamping (metal case of thedetonator). The better the punctiform initiation, the weaker will be theintensity of the detonation wave so that different starting distances inthe individual directions will be the effect. The result is therefore anaccidentallyformed, that is, 'an unsymmetrical detonation wave. If thediameter of the detonation rod is increased, the symmetry of thedetonation start will improve because the initiation intensity hasincreased. However, the starting point of the detonation wave will thenbe equally probable over the entire cross section of the surface contactof the detonator rod. Therefore, because the starting point remainsuncertain, it would be impossible to achieve a symmetrical detonationwave.

In accordance with the present invention, there is provided a detonatorhaving punctiform initiation of the detonation of high intensity whichincludes an explosive charge of a faster detonation velocity explosiveimbedded in a charge of a slower acting explosive. Such a constructionassures an exact punctiform initiation of the detonation with such ahigh initiation intensity, that a uniform propagation of the detonationin all directions will occur. This is effected by a detonator whichconsists of the two explosives of difierent detonation velocity.

Accordingly it is an object of the invention to provide 3,377,953Patented Apr. 16, 1968 a detonator having a uniform propagation ofdetonation in all directions.

A further object of the invention is to provide a detonator having exactpunctiform initiation of the detonation with such a high initiationintensity that a uniform propagation of the detonation in all directionswill be insured.

A further object of the invention is to provide a deton'ator which issimple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there are illustrated and described preferredembodiments of the invention.

In the drawings:

FIG. 1 is a schematic sectional representation of a detonatorconstructed in accordance with the invention;

FIG. 2 is a view similar to FIG. 1 of another embodiment of theinvention; and

FIG. 3 is a view similar to FIG. 1 of still another embodirnent of theinvention.

Referring to the drawings, in particular, the invention embodied thereincomprises a detonator which includes a slower explosive 1 of arelatively large size in which is embedded a conical tip 2' of a fasteracting explosive 2. The construction, in accordance with the invention,is such that a non-symmetrical detonation is not probable. If aneccentric detonation wave is started, for example, at the tip of thearrow 3, the wave which is propagated designated 4 will strike after ashort period of time the tip 2 of the explosive 2. Since the conical tip-2 of the faster-acting explosive 2 is surrofi'nded on all sides by theslower acting explosive 1, the release of the detonation wave in thecone apex takes place with full intensity. The detonation wave showsthen at a later point a course or wave path indicated 5. Thus, despitethe originally eccentric detonation wave in the explosive '1, an axiallysymmetrical eccentric detonation wave is released in the cone apex. Thefollowing explosive charge proper is therefore initiated 'axiallysymmetrically by the symmetrically oriented detonation wave frontportion 5a.

In the embodiment of the invention indicated in FIG. 1, it is possibleto rectify detonation initiations within 3.5 mm. eccentricity as shownby tests.

In FIG. 2 another embodiment is indicated in which a slower explosive 7surrounds a cone apex 8' of a faster acting explosive 8. An additionalcone of a faster-acting explosive 9 is arranged above the cone 8 in anapex man ner. With this design of detonator as shown in FIG. 2, evengreater eccentricities can be rectified so that the problem of apunctiform initiation with high intensity is possible.

As an example, the following explosives are used: For the detonator part7, tetryl pressed with about 2% wax and graphite; for the detonator part8, for example, a cast explosive of from about 15% TNT and hexogen witha grain size of less than m. The part 9 may advantageously comprise ahighly pressed nitropenta with 2% Wax.

The detonator according to FIG. 2 operates so that each detonation wavein part 9, no matter where it is released on the surface, is alwaysconducted first to the cone apex of the part 9 and thus also to the apexof the part 8. The detonation waves in part 7 can thus have no harmfuleffect in any case on the axial symmetrical design of the detonationwave in part -8.

The invention described by way of example in respect to an axiallysymmetrical detonator can be applied to all other detonators, forexample, for releasing a ring-shaped detonation (cylindrical detonationwave).

In the embodiment of FIG. 3, initiation of the detonation in a conicalexplosive charge of a faster explosive is conducted to the apex of thelatter where an annular body 11 of a faster explosive is assembled withintermediate bodies 12 and 13. The intermediate bodies 12 and 13 aremade of a slower acting explosive.

In accordance with still a further embodiment of the invention, theindividual charges in FIGS. 1 and 2 are joined together, preferably withan adhesive such as a plastic adhesive.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise Without departing from such principles.

What is claimed is:

1. A detonator having punctiform initiation of the detonation of highintensity for obtaining an axially symmetrical detonation, comprising aslow acting explosive charge, and a fast-acting explosive charge havinga conical tip imbedded within the slow acting charge, and means forinitiating detonation at a point on said slow acting explosive charge ata location close to the axis of said fast acting explosive charge.

2. A detonator, according to claim 1, wherein there are at least twoslow acting explosive charges, one each surrounding the respectiveconical tip portion of each fast-acting explosive charge.

3. A detonator, according to claim 1, including adhesive means bondingsaid explosive charges together.

4. A detonator, according to claim 1, wherein said fastacting explosiveis a cast explosive of around 15% TNT and 85% hexogen.

5. A detonator having punctiform initiation of a detonation of highintensity, for obtaining an axially symmetrical detonation, comprising aslow acting explosive charge, and a fast-acting explosive chargeimbedded within the slow acting charge, said fast-acting explosivecharge including a conical tip imbedded in said slow acting charge, anda second fast-acting explosive having a conical tip portion arrangedwith its apex abutting the apex of said first fast-acting explosivecharge, said slow acting explosive charge surrounding the conical tip ofsaid fastacting and said second fast-acting explosive charges.

6. A detonator having punctiform initiation of the detonation of highintensity for obtaining an axially symmetrical detonation, at least twofast-acting explosive charges each having conical tip portions and beingarranged with their apexes abutting, and a plurality of slow actingexplosive charges surrounding the conical tip portions of saidfast-acting explosive charges.

7. A detonator, according to claim 6, wherein one of said fast-actingexplosives is a cast explosive of around 15 TNT and hexogen and theother is pressed with a nitropenta and 2% wax, and the slow actingexplosive is pressed tetryl and 2% wax and graphite.

References Cited UNITED STATES PATENTS 2,396,978 3/1946 Amthor 102-562,604,042 7/1952 Cook. 3,100,445 8/ 1963 Poulter 102-24 3,285,01211/1966 Larue 102l01 X BENJAMIN A. BORCHELT, Primary Examiner.

V. R. PENDEGRASS, Assistant Examiner.

